FORD EXPLORER ENGINE PROBLEM

1993 Ford Explorer • 170,000 miles

Truck starts and runs fine with normal idle, but once engine is warm has a "chugg chugg" when the gas is applied and if I push it down all the way it seems to stall, gets quiet like the engine is dead but it is still running. Changed wires, plugs, air filter, inspected and cleaned the MAF, IAC, trottle/air intake plate, (there was a small hole in the plastic intake tube between the MAF and the Throttle, taped to fix it), new cat converter, O2 sensor, serpintine belt, selenoid, and a number of other small things. I cant seem to figure out the cause of the chugging. Tried fuel injector cleaner(use 1 about every 2000mi), checked repeatedly for vacuum leaks, tried valve seals and gasket seals (had some white smoke coming from exhaust on startup but now since has gone)(also somtimes the exhaust smells like rotten eggs when it starts to chugg out)and just about everthing I could think of. My oil has a greenish look(i added engine restore and a bit of lucas stabilizer) but no sign of water or antifreeze, my antifreeze has no sign of oil either. PLEASE HELP me figure this out, I really need my truck as its paid for and would like to fix it, but being on a fixed income money is hard to come by, which is why I have'nt taken her to the shop yet. Thank you so much!